President Bush (search) said he was glad he and Vice President Dick Cheney (search) met Thursday behind closed doors with the panel investigating what went wrong with U.S. intelligence before the Sept. 11, 2001, terror attacks.

Speaking in the White House Rose Garden after the meeting, Bush described it as "a good conversation. ... It was wide-ranging. It was important. It was just a good discussion.

"They had a lot of good questions. I'm glad I did it. I'm glad I took the time. It's important that they asked the questions they asked ... I answered every question that they asked," Bush said, declining to describe the details of the meeting but acknowledging that Al Qaeda is still a threat to the United States.

The 10 commissioners arrived at the White House at about 9:15 a.m. and gathered around Bush and Cheney, who were seated on chairs near the fireplace in the Oval Office. White House counsel Alberto Gonzales and two unidentified members of his staff joined the session, which began sharply at the scheduled 9:30 a.m. appointment time.

"Ninety-nine percent of the questions were directed to the president," one of two participants in the Oval Office meeting that spoke to Fox News said. "He answered them all ... and didn't have to turn to anyone for guidance," said another. "He knew them all."

Sources also told Fox News "everyone got to ask all the questions they could think of." Some of the questioning was sharp but the president answered all questions in a "direct and businesslike manner."

At one point, one participant told Fox News, one of the commissioners apparently delivered a lengthy statement not unlike those in the public sessions. The president teased a couple of the commissioners about that but in a way that got a laugh even from Richard Ben-Veniste. One source said the whole session "was in very good humor." A second said, "The atmosphere was very cordial."

One of the participants said the commission learned some things and the president learned some things. He also told Fox News the president was able to straighten out some things where there had been inconsistencies between some other people's testimony. Cheney was said to have filled in some things and "was a real help."

"It was a big success for all parties," said one of the sources. And he said it was clear from the session that "the president really does want to work with us now." The second participant said the president was confident and knowledgeable and was "really interested in our views."

After the meeting, Bush said that his counsel never advised him not to answer any questions. He said Cheney too answered all the questions posed to him.

"I was impressed by the questions, I think it helped them understand how I run the White House,' Bush said. "I wanted them to know how I set strategy, how we run the White House, how we deal with threats."

After the meeting, the commission released a statement in which it thanked the two leaders. 

"The commission found the president and the vice president forthcoming and candid. The information they provided will be of great assistance to the commission as it completes its final report. We thank the president and the vice president for their continued cooperation with the commission," the statement read.

Bush said he did not want to go into details of the report because he thought they would come out when the panel publishes its report in July. He did, however, say that Al Qaeda continues to be a threat and the United States is still vulnerable to attack.

"Al Qaeda still exists, Al Qaeda's dangerous, Al Qaeda hates us, and we have to be correct 100 percent of the time in defending America and they've got to be right once. And therefore we are vulnerable," Bush said.

"We, the government, at all levels, are working long hours to protect America. We're doing the best we can. The best way to secure America, however, is to stay on the offensive and bring those people to justice before they harm America again," he added. 

Bush and Cheney were not under oath, and no recording of the proceedings took place. The White House said it has no plans to report the remarks by the president and vice president -- in part, aides say, because much of the discussion is classified.

The commission's interviews with former President Clinton and former Vice President Al Gore were recorded.

White House Press Secretary Scott McClellan said Thursday that the meeting was private and will be reflected in the commission's final report.

"This is a good opportunity for the president to sit down with members of the commission and talk with them about the seriousness with which we took the threat from Al Qaeda (search), the steps we were taking to confront it and how we have been responding to the attacks of Sept. 11," McClellan said Thursday, shortly after the session began.

The White House claimed it was sensitive about the separation of powers (search) issue, giving authority to a commission created by Congress to grill the president.

"It is extraordinary for the president to sit down with a legislatively-created commission, but the circumstances [of Sept. 11] were extraordinary," McClellan said after the session ended. 

Bush "has provided the 9/11 commission unprecedented access to information including the nation's most sensitive national intelligence documents. He very much supports the work of the commission. He looks forward to seeing their recommendations and acting on their recommendations."

Peter Wallison, former White House counsel in the Reagan administration, said he believes the administration wanted the session kept private in order to make sure that a precedent was not set about executives testifying to congressional entities.

"It's important for this commission to get information from the president and vice president. The commission could not have done its work without getting information from them," Wallison said. But, he added, "This is very, very unusual for a president to meet with an organization established by Congress in an investigative mode. In order to make sure that it's not a regular thing for presidents and vice presidents to do, it was important to set ground rules."

One analyst suggested the White House was refusing to allow a tape recording or transcript of the session because it wouldn't give the administration any political advantage.

"If they thought it would help him, they'd televise it," James Thurber, director of American University's Center for Congressional and Presidential Studies (search), said of White House advisers' decision to keep the meeting's contents under wrap. "And obviously they don't think it will help him, and so they are not."

"The thing that is most unfortunate is that there won't be even a redacted transcript. The American people deserve to hear the president's explanation," said Jack Quinn, former White House counsel and chief of staff to Vice President Al Gore.

McClellan said the interview should not be seen as testimony or an attempt by the panel to find out whether Bush is to blame for not preventing the attacks. Instead, Bush was contributing to the process of learning from Sept. 11, McClellan said, by putting into perspective the substantial information the White House has already provided.

"The commissioners will speak for themselves over time. They will let you know whether they thought it was a fruitful series of discussions. I think they did. I think they found it to be useful," Bush said. 

The process, however, has taken on something of an adversarial tone, with Democrats saying the president abdicated his responsibility before the attacks and Republican lawmakers charging that commissioner Jamie Gorelick (search), President Clinton's deputy attorney general, should be forced to testify in front of the panel, since they say she was intimately involved with building the bureaucratic wall that separated criminal prosecutions and terrorism investigations before the attacks.

Republican Sen. Mitch McConnell, R-Ky., said Wednesday that the commission may not have been intended as a partisan investigation, but it sure is taking a combative tone.

"My understanding of the 9/11 commission was that it was to impartially determine the facts and make non-partisan recommendations on how to go forward. But so far, the 9/11 commission's descent into 'gotcha' questioning has only highlighted a tendency to fight each other rather than the terrorists. Unfortunately, while American politicians are busy blaming each other, the terrorists are busy plotting our doom."

Relatives of the Sept. 11 attacks said they hoped the commissioners would ask Bush and Cheney whether the administration was inattentive when intelligence warnings in the summer of 2001 increasingly pointed to a domestic attack, and whether the government's emergency response on Sept. 11 too slow.

"The purpose is not to lay blame, but to assess possible reforms," said Kristen Breitweiser of Middletown, N.J., whose husband, Ronald, was killed in the World Trade Center.

One key question Bush was likely to have been asked is how he dealt with information one month before the attacks that indicated Al Qaeda (search) seemed interested in hijacking a plane and planning attacks with explosives within the United States. Bush has said previously there was nothing in that Aug. 6 memo that indicated "something is about to happen in America."

Bush and Cheney were also expected to confront questions about whether they were too distracted by the possibility of attacking Iraq to pay attention to warnings of an impending terror attack. Reporter Bob Woodward (search) and former White House terrorism coordinator Richard Clarke (search) separately contend that Bush and Cheney were fixated on finding an Iraqi link to the attacks. The administration has denied it.

McClellan said the president spent the past few days reviewing materials from the period around the attacks to refresh his memory and talking with the vice president and several other senior officials, including Chief of Staff Andy Card, who first told him of the attacks during a trip to Sarasota, Fla.

The effect of Bush and Cheney's classified Q&A session with the commissioners might not be known until the panel releases its final report, which is due out this summer, about three months before the fall presidential election and at the start of the Democratic National Convention.

"It's very important because of the timing, just before the election," Thurber said. Bush "is very strong in the polls on homeland security, and this may undermine it a little bit."

But Washington Times Senior White House Correspondent Bill Sammon argued that "when you talk about this, it reminds people of Bush's leadership after 9/11, which is a great asset. ... Most Americans don’t think that President Bush or President Clinton could have realistically prevented these unimaginable attacks of 9/11. ... I just don’t see where there is a fruitful political path here for either side."

Washington Post White House Correspondent Dana Milbank told Fox News that the meeting may even boost Bush "by turning attention to terrorism where the president is the strongest."

Fox News' Peter Brownfeld, Jim Angle, Wendell Goler and Major Garrett and The Associated Press contributed to this report.